But the boat mercifully came back down. Oracle went on to easily win the race, before Team NZ caught their collective breath and made the start line for Race 9.
The challengers were leading and the two boats were neck and neck up the vital third, upwind leg when the wind proved too much and the organisers abandoned the race.
But all everyone was talking about was the moment of near-disaster in Race 8.
Team NZ were leading a re-energised Oracle Team USA in a tacking duel when the unthinkable nearly happened. On a tack, which looked like they were trying to pull off a foiling manoeuvre to stave off the American challenge, the Kiwi wingsail didn't handle the change. Instead of popping, to drive the tack, it stuck in place - changing it from a sophisticated piece of aerodynamics to a wall against which the wind battered.
Painfully, horrifyingly, the big cat hung a hull high in the wind - an accident waiting to happen - before somehow righting itself.
"It was a routine tack but when the wing doesn't tack and the boat does, you can end up in trouble," said a remarkably sanguine ETNZ skipper Dean Barker after the race.
The race was lost but the Cup is still up for grabs; the score is now 6-0 and Oracle have worked off their two-race, two-point penalty.
Before that, it had looked good for Team NZ though a revamped Oracle boat came out more competitive in the heavier winds and rougher seas and after some boatshed changes. OTUSA skipper Jimmy Spithill mucked up the start and the two boats turned into the vital upwind leg with Team NZ ahead by eight seconds and about 100m.
Then something else we haven't seen, except in Race 4 - OTUSA made ground upwind, shortening the Kiwi lead, tacking well and putting the pressure on. As the lead dropped and the tacks got tighter, ETNZ were still ahead and this looked like it would be the tightest race yet.
But then came the tack and the excruciating near-flip. That was the race and OTUSA won easily, by 52s but the time wasn't important this time - just finishing was a triumph for the Kiwis.
If they hadn't, the campaign would probably have ended in a massive floating mess of carbon fibre.
There will be two more races tomorrow, with conditions likely to be similar to today.